Inventing a whole new way to cool things

Typical refrigeration systems remove heat from the refrigeration space through the gas, which cools as it expands. As efficient as this process is, some of the gases we use are not particularly environmentally friendly.

However, there are several ways to make a material absorb and radiate heat energy.

Developed by researchers at the Lawrence Berkeley National Laboratory and the University of California at Berkeley in the US, the new method exploits how energy is stored or released when matter changes, such as when solid ice turns into liquid water.

Heat up a piece of ice and it will melt. What we cannot see so easily is that the melt absorbs heat from its surroundings, effectively cooling it.

One way to make ice melt without adding heat is to add a few charged particles or ions. Salting roads to prevent icing is a common example of this in practice. The ion cycle also uses salt to change the phase of the liquid and cool the environment.

“The nature of refrigerants is an open question,” says mechanical engineer Drew Lilly of Lawrence Berkeley National Laboratory in California. “Nobody has come up with a workaround that is cool, efficient, safe, and environmentally friendly. We think the ionic cycle has potential.” All of these goals will be achieved if they are properly achieved.

The researchers modeled the ion cycle theory to show how it can rival or even improve the efficiency of refrigerants in use today. The current passing through the system can move the ions in it, shifting the melting point of the substance and changing the temperature.

The team also performed experiments using iodine and sodium salt to dissolve ethylene carbonate. This common organic solvent is also used in lithium-ion batteries and is produced using carbon dioxide as a starting material.

A temperature shift of 25 degrees Celsius (45 degrees Fahrenheit) has been measured with a charge of less than one volt in the experiment, a result that is superior to what has hitherto been achieved by other calorimetric methods.

“We’re trying to balance three things: the GWP of the refrigerant, the energy efficiency and the cost of the equipment itself,” says mechanical engineer Ravi Prasher of Lawrence Berkeley National Laboratory. looks very promising in all these aspects.”

Vapor compression systems currently used in refrigeration processes are based on gases with a high global warming potential, such as various hydrofluorocarbons (HFCs). Signatories to the Kigali Amendment have committed to reducing their production and consumption of HFCs by at least 80% over the next 25 years, and ion axial cooling can play a key role in this.

Researchers now need to take the technology out of the lab into practical systems that can be used commercially and scaled without any problems. Finally, these systems can be used for both heating and cooling.

The study is published in the journal Science.

Source: Science Alert